Best three man group? With some Criteria.

[RDawg816]

Shm/War/Mnk will be a fine trio for your group.

Some things to consider....a rogue would die less in those "5 pull scenarios" because all you have to do is tell your dad to stay hidden until it's under control. Even if you 2 wiped, he would be fine. Also, the best way to root CC those bad pulls is to have the puller run/walk backwards (depending on scenario and location) and let you root them in a spaced out manner. Then you can slow the last one and malo+slow+re-root the adds as you get to them.

As for aggro....usually you'll want to slow early, which will mean the shaman will be tanking for a bit, or you'll have to root everything first. I usually tanked most mobs while levelling, and if we had a particularly hard/resistant mob (like golems in the Hole, for example) I would root them first, then slow+malo and then tell the melee to engage.
Beyond that, it will depend on who has the better weapons, or who lands what procs, to determine who has aggro. Taunt is ok, but it's not an automatic thing.

As for the Shm/Monkx2 suggestion, that would work....however, you'd have to have the shaman loot everything, and then later on if you wanted to take out bigger targets, it's really nice to have a warrior. On top of that, you have no competition for gear with 1 leather, 1 chain, and 1 plate class...whereas on the 2 monk trio you'd have heavy competition with the 2 monks.

[Yttrium]

Also with that Trio you can just play 3 Iksar and start in the same zone. Full group regen is great, and Kunark is a great place to level.

[Doctor Jeff]

I love these posts, I look forward to the follow up when you are "unjustly" banned for boxing.

[Philaw]

SHM/Warrior/Druid

slow and thorns do a lot of work and you have enough healing and regen to live through most ugly pulls.

[Naethyn]

War + Rog + Clr is my favorite trio. Have your dad play the rogue or warrior. Have your best player on the cleric. A good cleric can memblur, single pull, cc, everything you really need.